I used the same Haiti strategy that I introduced in my last PB, but this time I had better luck so I got the world record :)

One major improvement that could still be made, which unfortunately also relies on RNG, is to add Denmark to your sphere via war, which is much faster since you can start the war before you're a GP. But that relies on Prussia being preoccupied with another war, for example the Dutch-Belgian war, or else they will intervene on Denmark's side. But it's still definitely doable if someone is willing to grind the RNG enough!